Solid state drives (SSDs), which allow the speed of data access to be higher than hard disk drives (HDDs), have recently been being used. An SSD includes a storage area made of a flash memory or the like, and also includes a controller (SSD controller), a cache, and a storage area.
When accessing data in such an SSD, a computer uses an AT Attachment (ATA) command, as in the case of an HDD, so as to transfer write and read data to an SSD controller.
It is known that a storage element used for the storage area of an SSD has a limitation in the number of writing and therefore a fault would occur when an SSD is used for a long time.
To address this, a self-diagnostic function called Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.) for early detecting a disk fault and predicting a failure is known as a technology for detecting a failure of an SSD or HDD before the failure occurs.
As a technique for protecting data stored in the SSD, there is also a method in which an SSD controller detects a failure in the SSD and causes the storage area to be in a read-only (ReadOnly) mode, thereby prohibiting writing of data to protect the storage area.
In an information processing apparatus provided with such a conventional SSD, however, when writing of data is prohibited in the SSD by causing the storage area to be in a read-only mode, a controller would sometimes notify the information processing apparatus of the success of writing at the point when write data is stored in a cache of the SSD. Thereby, when an attempt is made to read data from an SSD, such a situation arises that data to be read is not saved in the SSD. This leads to a problem of reduction in reliability.
Japanese National Publication of International Patent Application No. 2010-521014 discloses an example of the related art.
“S.M.A.R.T. Attribute Annex”, Sep. 30, 2005, [Mar. 21, 2012 searched], The Internet URL:http://www.t13.org/documents/UploadedDocuments/docs2005/e05148r0-ACS-S MARTAttributesAnnex.pdf) discloses a related technology.